Is there anyway to reprogram the automatic(15mph) door locks without taking it to the dealer? It is on a 99' z71 ext. cab. I also have a 2001 Tahoe and it can reprogrammed by turning the key on and pressing a series of buttons. Tried the same procedure with my truck but it didn't work. Thanks for the help.

Nope. That procedure only works on 00 and up. Dealership is the only way to get it done.